This example, which is based on FreeRTOS, demonstrates how to stream audio data, with a publicly available and widely used protocol constant overhead byte stuffing (COBS), from a microcontroller to a host system.
Provide feedback on this code example.
- ModusToolbox™ software v3.0 or later (tested with v3.0)
- Board support package (BSP) minimum required version: 4.0.0
- Programming language: C
- Associated parts: All PSoC™ 6 MCU parts
- GNU Arm® embedded compiler v10.3.1 (
GCC_ARM) - Default value ofTOOLCHAIN - Arm® compiler v6.13 (
ARM) - IAR C/C++ compiler v8.42.2 (
IAR)
- PSoC™ 6 Wi-Fi Bluetooth® prototyping kit (
CY8CPROTO-062-4343W) – Default value ofTARGET
This example uses the board's default configuration. See the kit user guide to ensure that the board is configured correctly.
This code example requires additional python packages, see section Setting up the python host application for more details.
Create the project and open it using one of the following:
In Eclipse IDE for ModusToolbox™ software
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Click the New Application link in the Quick Panel (or, use File > New > ModusToolbox™ Application). This launches the Project Creator tool.
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Pick a kit supported by the code example from the list shown in the Project Creator - Choose Board Support Package (BSP) dialog.
When you select a supported kit, the example is reconfigured automatically to work with the kit. To work with a different supported kit later, use the Library Manager to choose the BSP for the supported kit. You can use the Library Manager to select or update the BSP and firmware libraries used in this application. To access the Library Manager, click the link from the Quick Panel.
You can also just start the application creation process again and select a different kit.
If you want to use the application for a kit not listed here, you may need to update the source files. If the kit does not have the required resources, the application may not work.
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In the Project Creator - Select Application dialog, choose the example by enabling the checkbox.
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(Optional) Change the suggested New Application Name.
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The Application(s) Root Path defaults to the Eclipse workspace which is usually the desired location for the application. If you want to store the application in a different location, you can change the Application(s) Root Path value. Applications that share libraries should be in the same root path.
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Click Create to complete the application creation process.
For more details, see the Eclipse IDE for ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mt_ide_user_guide.pdf).
In command-line interface (CLI)
ModusToolbox™ software provides the Project Creator as both a GUI tool and the command line tool, "project-creator-cli". The CLI tool can be used to create applications from a CLI terminal or from within batch files or shell scripts. This tool is available in the {ModusToolbox™ software install directory}/tools_{version}/project-creator/ directory.
Use a CLI terminal to invoke the "project-creator-cli" tool. On Windows, use the command line "modus-shell" program provided in the ModusToolbox™ software installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ software tools. You can access it by typing modus-shell in the search box in the Windows menu. In Linux and macOS, you can use any terminal application.
The "project-creator-cli" tool has the following arguments:
| Argument | Description | Required/optional |
|---|---|---|
--board-id |
Defined in the <id> field of the BSP manifest |
Required |
--app-id |
Defined in the <id> field of the CE manifest |
Required |
--target-dir |
Specify the directory in which the application is to be created if you prefer not to use the default current working directory | Optional |
--user-app-name |
Specify the name of the application if you prefer to have a name other than the example's default name | Optional |
The following example clones the "Audio Streaming" application with the desired name "MyAudioStreaming" configured for the CY8CKIT-062-WIFI-BT BSP into the specified working directory, C:/mtb_projects:
project-creator-cli --board-id CY8CKIT-062-WIFI-BT --app-id mtb-example-audio-streaming --user-app-name MyAudioStreaming --target-dir "C:/mtb_projects"
Note: The project-creator-cli tool uses the git clone and make getlibs commands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mtb_user_guide.pdf).
In third-party IDEs
Use one of the following options:
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Use the standalone Project Creator tool:
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Launch Project Creator from the Windows Start menu or from {ModusToolbox™ software install directory}/tools_{version}/project-creator/project-creator.exe.
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In the initial Choose Board Support Package screen, select the BSP, and click Next.
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In the Select Application screen, select the appropriate IDE from the Target IDE drop-down menu.
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Click Create and follow the instructions printed in the bottom pane to import or open the exported project in the respective IDE.
-
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Use command-line interface (CLI):
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Follow the instructions from the In command-line interface (CLI) section to create the application, and then import the libraries using the
make getlibscommand. -
Export the application to a supported IDE using the
make <ide>command. -
Follow the instructions displayed in the terminal to create or import the application as an IDE project.
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For a list of supported IDEs and more details, see the "Exporting to IDEs" section of the ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mtb_user_guide.pdf).
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Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.
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Program the board using one of the following:
Using Eclipse IDE for ModusToolbox™ software
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Select the application project in the Project Explorer.
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In the Quick Panel, scroll down, and click <Application Name> Program (KitProg3_MiniProg4).
Using CLI
From the terminal, execute the
make programcommand to build and program the application using the default toolchain to the default target. The default toolchain and target are specified in the application's Makefile but you can override those values manually:make program TARGET=<BSP> TOOLCHAIN=<toolchain>Example:
make program TARGET=CY8CPROTO-062-4343W TOOLCHAIN=GCC_ARM -
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After programming, the application on the PSoC™ 6 starts automatically.
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To check that the audio data is streamed to the host you need to setup the python host application as described in the next section
On Windows, use the command line "modus-shell" program provided in the ModusToolbox™ software installation instead of a standard Windows command-line application. To install the additional python packages do the following on CLI:
python -m venv .venv
source .venv/Scripts/activate
python -m pip install -r host_app/requirements.txt
To start the host application you can start either the rtstream_simple.py or the rtstream_rich.py.
The real time streaming simple, permanently outputs the timestamp of the received audio package and a few audio samples. To start that host application on CLI run:
python -m host_app.rtstream_simple.py
Figure 1. Real time streaming simple
The real time streaming rich, permanently outputs the timestamp of the received audio package and a average timestamp delta. To start that host application on CLI run:
python -m host_app.rtstream_rich.py
Figure 2. Real time streaming rich
You can debug the example to step through the code. In the IDE, use the <Application Name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ software user guide.
Note: (Only while debugging) On the CM4 CPU, some code in main() may execute before the debugger halts at the beginning of main(). This means that some code executes twice – once before the debugger stops execution, and again after the debugger resets the program counter to the beginning of main(). See KBA231071 to learn about this and for the workaround.
This code example streams audio data over UART in realtime. The audio data are encoded into Protocol buffer messages and framed for UART transport using Constant overhead byte stuffing (COBS). It is based on FreeRTOS which comes with a strong support for AWS cloud connectivity. On the host side, a few lines of Python code reverse the encoding and deliver the audio data including meta-data for further processing steps like signal processing or AI/ML inference.
Table 1. Application resources
| Resource | Alias/object | Purpose |
|---|---|---|
| PCM/PDM (HAL) | pdm_pcm | To interface with digital microphones |
| UART (HAL) | cy_retarget_io_uart_obj | UART HAL object used by Retarget-IO for the debug UART port |
| Clock (HAL) | audio_clock | To configure the audio subsystem clock |
| Clock (HAL) | pll_clock | To configure the PLL clock |
| Resources | Links |
|---|---|
| Application notes | AN228571 – Getting started with PSoC™ 6 MCU on ModusToolbox™ software AN215656 – PSoC™ 6 MCU: Dual-CPU system design |
| Code examples | Using ModusToolbox™ software on GitHub Using PSoC™ Creator |
| Device documentation | PSoC™ 6 MCU datasheets PSoC™ 6 technical reference manuals |
| Development kits | Select your kits from the Evaluation board finder page |
| Libraries on GitHub | mtb-pdl-cat1 – PSoC™ 6 peripheral driver library (PDL) mtb-hal-cat1 – Hardware abstraction layer (HAL) library retarget-io – Utility library to retarget STDIO messages to a UART port psoc6-middleware – Links to all PSoC™ 6 MCU middleware cobs – Library for encoding and decoding according to COBS methods nanopb – Small code-size protocol buffers implementation in ANSI C |
| Tools | Eclipse IDE for ModusToolbox™ software – ModusToolbox™ software is a collection of easy-to-use software and tools enabling rapid development with Infineon MCUs, covering applications from embedded sense and control to wireless and cloud-connected systems using AIROC™ Wi-Fi and Bluetooth® connectivity devices. PSoC™ Creator – IDE for PSoC™ and FM0+ MCU development. |
Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.
For PSoC™ 6 MCU devices, see How to design with PSoC™ 6 MCU - KBA223067 in the Infineon developer community.
Document title: CE235492 - PSoC™ 6 MCU: Audio streaming
| Version | Description of change |
|---|---|
| 1.0.0 | New code example |
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